Mill roll changing arrangement

ABSTRACT

A rolling mill having a roll changing sledge is provided with latching means connecting a lower set of chocks with an upper set to permit raising of a lower roll with the upper roll, and normally disengaged load transfer posts extending between one set of chocks and a lower set of chocks to permit transfer of the weight of the upper roll to the sledge for simplified and rapid roll changing. The load transfer posts permit the use of different sizes of working rolls, the posts being repositioned after separation of the rolls to a roll supporting position by minor axial displacement of the sledge. The arrangement is well suited to automated roll changing.

iJnited gtates Patent [191 Field [54] MILL ROLL CHANGING ARRANGEMENT [75] inventor: Michael Frank Field, Dollard des Ormeaux, Quebec, Canada [73] Assignee: Dominion Engineering Works Limited, Montreal, Canada [22] Filed: Jan. 4, 1972 [21] Appl. No.: 215,312

[52] U.S. Cl ..72/239 [51] Int. Cl. ..B2lb 31/08 [58] Field of Search ..72/238, 239

[56] References Cited UNITED STATES PATENTS 3,438,234 4/1969 Adour ..72/239 X 3,475,940 11/1969 Petros, Jr. ..72/239 3,675,456 7/1972 Siearin ..72/239 1 3,733,877 [4 1 May 22,1973

2,037,210 4/1936 Buente ..72/235 3,171,304 3/1965 Sims et al. ..72/241 Primary Examiner-Milton S. Mehr Attorney-Henry C. Westin [57] ABSTRACT A rolling mill having a roll changing sledge is provided with latching means connecting a lower set of chocks with an upper set to permit raising of a lower roll with the upper roll, and normally disengaged load transfer posts extending between one set of chocks and a lower set of chocks to permit transfer of the weight of the upper roll to the sledge for simplified and rapid roll changing. The load transfer posts permit the use of different sizes of working rolls, the posts being repositioned after separation of the rolls to a roll supporting position by minor axial displacement of the sledge. The arrangement is well suited to automated r011 changing.

7 Claims, 3 Drawing Figures MILL ROLL CHANGING ARRANGEMENT This invention is directed to a rolling mill and to a method of changing the rolls of a mill.

In the operation of rolling mills, such as four-high steel rolling mills, generally used in rolling hot strip, the ability to change the working rolls safely and rapidly is of considerable economic importance.

Prior roll changing systems, which dealt with changes in the back-up rolls have required special provisions, such as push-out rams, turntables and extensive removeable sections to provide sufficient space for carrying out roll changes. Such systems often involve separate provisions to deal with changing of back-up rolls and changing of working rolls, including the use of spacers of different thickness to provide effective chock stacking, or counter-weighted porter bars for handling the working rolls.

The present invention provides a rolling mill having a single roll transportation sledge and chock spacing load transfer means permitting the transportation of selected ones of the rolls from the mill to the aisle for rapid roll changing using a crane directly.

The invention also provides roll changing capability which is unaffected by the relative diameters of the work rolls being changed, so that changes in mill setup may be rapidly dealt with.

Owing to the increased complexity of strip mills and the high rates of production obtainable with automated control systems, such as computers, the mill downtime for roll replacement or changing assumes increasing significance. The present invention provides a roll changing facility of great flexibility, well suited to auto mation or computer control for the roll removal step and the roll replacement step in carrying out roll changes.

In addition to cost advantages afforded by the speedup in roll changing, safety of workers is promoted as no physical handling of major components within the mill is necessary.

While the illustrated embodiment is directed to a four-high mill, it will be evident that the advantages of the subject invention obtain also with other types of mills, such as two-high mills.

Certain embodiments of the invention are described, reference being made to the accompanying drawings wherein:

FIG. 1 shows a four-high mill embodying the invention;

FIG. 2 shows a front view at 2-2 of FIG. 1; and

FIG. 3 is a detail view of FIG. 1, but having the upper chocks in the raised position.

Referring to the drawings, the mill includes end frames 12, each having a window 14 to contain the roll chocks. The mill rolls comprise upper and lower backup rolls 16, 18 and upper and lower work rolls 20, 22. The journals of each roll are mounted in bearing chocks, the rolls 16, 18 being rotatably mounted in chocks 26, 28, respectively, while the rolls 20, 22 are rotatably mounted in chocks 30, 32, respectively.

The top back-up roll 16, mounted in chocks 26 is supported by a hydraulic roll balance 36 comprising a yoke 38 carrying balance rods 40, 42 which support window slide members 44 to which the chocks 26 are keyed by way of lugs 27. An hydraulic balance cylinder 46 and piston 48 connected by rod 49 to the yoke 38 serve to raise the roll 16 when the mill is unloaded. Ad-

justment and loading of the mill is effected by the screwdown, a portion 50 thereof being shown.

The top working roll 20, mounted in chocks 30, is loosely keyed to the chock 26 of the back-up roll 16, by way of lugs 37 mounted in slots 39, for raising up of the top working roll 20 by the roll balance mechanism.

Similarly, the chocks 32 of the lower working roll 22 are loosely held between leg portions 31 of the chocks 30, being slidably secured by retractable pins 33 extending into slots 35. This manner of connection retains the chocks 32 in loose supported relation with chocks 30, while permitting desired roll cooperation.

The lower back-up roll 18 is mounted between chocks 28 which are carried on sled halves 53 by rocker plates 54. The rocker plates 54 permit transference to the frame 12 of working loads exerted on the rolls by way of the roll chocks and sled.

Spacing jacks 56 between the chocks 30 and 32 of the work rolls are provided with hydraulic fluid at 57, 58 and serve to maintain the working gap at the nip formed between rolls 20 and 22.

In order to practice the present invention there are provided pairs of spacer thrust members extending upwardly from the chocks 28 of the bottom back-up roll.

The thrust members 70 fit into recesses 72 formed in the bottom faces of the chocks 30 of the top working roll 20.

Thus, when the normally off-set thrust members or posts 70 are moved axially into coincidence with the recesses 72, and the chocks 30 lowered downwardly to engage the posts, the weight load of the working rolls and chocks is then transferred from the lugs 37 of chock 26 to the sled 53. This leaves lugs 37 free to slide axially in slots 39 of chock 26, for easy axial displacement of the working rolls and chocks from the mill.

In operation, when it is necessary or desired to change the work rolls 20, 22, the work rolls are raised upwardly away from the lower backing-up roll 18. This is effected by retracting the screwdown 50 and moving the balance piston 48 upwardly by hydraulic pressure to raise the yoke 38, carrying with it the top back-up chocks 26, the top working chocks 30 and the lower working chocks 32, and the associated rolls.

The hydraulic supply hoses (not shown) supplying connections 57, 58 for the work roll jacks 56 are disconnected.

The sled 53, carrying the back-up roll 18, is then unlatched from the mill frame 12 and displaced axially a short distance to bring the posts 70 of the chocks 28 into vertical coincidence with the facing recesses 72 of chocks 30. The balance piston 48 is then lowered to transfer to the posts 70 the load of the working rolls 20, 22 and their chocks.

The sled 53 may then be moved axially out into the aisle adjacent the machine for desired servicing and/or changing of the working rolls 20, 22 for rapid subsequent return into the mill.

Owing to the arrangement provided, there is a minimum of handling time required and direct crane access may be utilized in handling the rolls with slings or straps. In the case of the top backing roll 16, the system may be arranged in a similar fashion to use the sled and bottom backing roll 18 for rapid changing of the backing roll or rolls.

The relative travel capability of the balance piston 48 is sufficient to accommodate a variety of sizes of working rolls and the related sizes of chock. The need for insertion by hand of intermediate chock spacers is substantially eliminated. The roll drives are disconnected by the pulling out of the rolls, driving spindles may be locked at the roll elevation prior to pull out. Fresh rolls when put into the mill are at the same elevation and will therefore reconnect automatically. While the posts 70 are shown extending upwardly from the bottom chocks 28, alternative arrangements are possible, such as, with the posts extending downwardly from the chocks 30. While the sled drive system is not shown, it will be evident that many existing sled systems may be readily adopted for this purpose.

The provision of an automated control to provide automatic roll-out of working rolls contemplates the provision of programmed raising of the top rolls by the roll balance system, carefully controlled displacement of the sled to effect alignment of the respective posts and recesses, lowering of the selected rolls into load transfer relation with the sled, and completion of sled roll out, carrying the rolls for changing into the aisle. Automated roll-in is effected in reverse.

In addition to facilitated roll handling and changing, safety in working conditions is greatly enhanced.

While the present embodiment is disclosed with reference to a sled, it will be understood that certain advantages thereof will be obtained using alternative forms of carriage, such as, roller or fluid supported carriages.

In accordance with the provisions of the patent statutes, I have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof.

I claim:

1. A rolling mill having a lower roll rotatably mounted in bearing chocks supported within the frame of the mill upon carriage means axially moveable from the mill frame; an upper roll rotatably mounted in hearing chocks superposed over said lower roll; attachment means securing the chocks of said upper roll to a movable upper portion of the mill for upward displacement of the upper roll and chocks from the lower roll and chocks; and fixed load bearing means extending from a pair of said chocks having a first disengaged position, to permit contact between rolls in working engagement, and a second engaged position to locate said upper roll chocks in stable supported relation on said carriage means, whereby in said disengaged position said rolls may cooperate in mutual working relation and in said engaged position said rolls and the related said chocks may be withdrawn from the mill on said carriage means.

2. The rolling mill as claimed in claim 1 having a pair of working rolls, and a pair of backing rolls in mutual supporting relation with said working rolls; said carriage means supporting by way of lower chocks the lower one of said backing rolls, said load bearing means extending between the lower chocks and the chocks of a said working roll when in said engaged position for withdrawal of said working roll from the mill on the carriage.

3. The rolling mill as claimed in claim 1 wherein said load bearing means comprise a plurality of substantially vertically extending posts, said posts in said disengaged position extending from selected ones of said chocks in axially disengaged relation with mating recesses in others of said chocks adjacent said selected chocks.

4. The rolling mill as claimed in claim 2 wherein said load bearing means comprises posts extending substantially vertically between the chocks of said upper working roll and the chocks of said lower backing roll.

5. The rolling mill as claimed in claim 4 wherein the individual chocks of said lower working roll are recessed within the corresponding individual chocks of said upper working roll.

6. The method of removing a roll assembly from a rolling mill having at least one upper roll assembly and at least one lower roll assembly mounted on carriage means positioned within the mill structure, each said roll assembly including bearing chocks to support the rolls in rotatable mounted relation in the mill, comprising the steps of displacing load applying means clear of said upper roll and raising said roll and associated chocks thereof towards an upper portion of the mill fixed structure away from the lower roll and roll chocks, unlatching said carriage means from the mill and axiaily repositioning said carriage means relative to the mill to interpose thrust load members fixed to the chocks of a said roll between respective ones of said upper and lower chocks by axial displacement of said lower roll and lower roll chocks with said carriage; lowering said upper roll and roll chocks onto said thrust members in supported relation therewith to transfer the load thereof to said carriage means, freeing the upper roll and chocks from said mill fixed structure; and axially displacing said carriage means and rolls supported thereon from the mill to provide substantially unrestricted access to said rolls for changing the rolls.

7. The rolling mill as claimed in claim 1 wherein said fixed load bearing means comprises a rigid post means, and wherein said second engaged position is spaced axially from said first position relative to the axes of rolls; and further wherein said stable supported relation is achieved by axial displacement of said lower roll chocks relative to said upper roll chocks. 

1. A rolling mill having a lower roll rotatably mounted in bearing chocks supported within the frame of the mill upon carriage means axially moveable from the mill frame; an upper roll rotatably mounted in bearing chocks superposed over said lower roll; attachment means securing the chocks of said upper roll to a movable upper portion of the mill for upward displacement of the upper roll and chocks from the lower roll and chocks; and fixed load bearing means extending from a pair of said chocks having a first disengaged position, to permit contact between rolls in working engagement, and a second engaged position to locate said upper roll chocks in stable supported relation on said carriage means, whereby in said disengaged position said rolls may cooperate in mutual working relation and in said engaged position said rolls and the related said chocks may be withdrawn from the mill on said carriage means.
 2. The rolling mill as claimed in claim 1 having a pair of working rolls, and a pair of backing rolls in mutual supporting relation with said working rolls; said carriage means supporting by way of lower chocks the lower one of said backing rolls, said load bearing means extending between the lower chocks and the chocks of a said working roll when in said engaged position for withdrawal of said working roll from the mill on the carriage.
 3. The rolling mill as claimed in claim 1 wherein said load bearing means comprise a plurality of substantially vertically extending posts, said posts in said disengaged position extending from selected ones of said chocks in axially disengaged relation with mating recesses in others of said chocks adjacent said selected chocks.
 4. The rolling mill as claimed in claim 2 wherein said load bearing means comprises posts extending substantially vertically between the chocks of said upper working roll and the chocks of said lower backing roll.
 5. The rolling mill as claimed in claim 4 wherein the individual chocks of said lower working roll are recessed within the corresponding individual chocks of said upper working roll.
 6. The method of removing a roll assembly from a rolling mill having at least one upper roll assembly and at least one lower roll assembly mounted on carriage means positioned within the mill structure, each said roll assembly including bearing chocks to support the rolls in rotatable mounted relation in the mill, comprising the steps of displacing load applying means clear of said upper roll and raisinG said roll and associated chocks thereof towards an upper portion of the mill fixed structure away from the lower roll and roll chocks, unlatching said carriage means from the mill and axially repositioning said carriage means relative to the mill to interpose thrust load members fixed to the chocks of a said roll between respective ones of said upper and lower chocks by axial displacement of said lower roll and lower roll chocks with said carriage; lowering said upper roll and roll chocks onto said thrust members in supported relation therewith to transfer the load thereof to said carriage means, freeing the upper roll and chocks from said mill fixed structure; and axially displacing said carriage means and rolls supported thereon from the mill to provide substantially unrestricted access to said rolls for changing the rolls.
 7. The rolling mill as claimed in claim 1 wherein said fixed load bearing means comprises a rigid post means, and wherein said second engaged position is spaced axially from said first position relative to the axes of rolls; and further wherein said stable supported relation is achieved by axial displacement of said lower roll chocks relative to said upper roll chocks. 